Indication of attraction domains for controlled planar motion of a ground vehicle

Abstract

A method and apparatus for operating a vehicle under manual or automatic steering mode is disclosed herein. An estimation of an attraction domain of stability is calculated for the vehicle using the vehicle's current position and orientation information relative to a target trajectory. If an unstable estimation of the attraction domain is determined, then the vehicle is operated in manual mode under control of an operator.

1. A method for providing stability indication of an automatic steered vehicle moving along a predefined path, comprising:
 calculating an estimation of an attraction domain of stability; and 
 providing an indication for automatic steering of the vehicle based on the estimation of the attraction domain. 
 
     
     
       2. The method of  claim 1 , wherein calculating the estimation of the attraction domain comprises calculating the estimation of the attraction domain using position data associated with the vehicle, orientation data associated with the vehicle, and a steered wheels angle associated with the vehicle. 
     
     
       3. The method of  claim 1 , wherein calculating the estimation of the attraction domain comprises calculating the estimation of the attraction domain using position data associated with the vehicle, orientation data associated with the vehicle, a steered wheels angle associated with the vehicle, and the predefined path. 
     
     
       4. The method of  claim 1 , wherein the estimation of the attraction domain comprises an ellipsoidal estimation of the attraction domain. 
     
     
       5. The method of  claim 1 , further comprising calculating a control signal based on position data associated with the vehicle, velocity data associated with the vehicle, orientation data associated with the vehicle, a steered wheels angle associated with the vehicle, and the predefined path. 
     
     
       6. The method of  claim 1 , wherein the steered wheels angle takes into account a differential in the angle of rotation of front wheels of the vehicle. 
     
     
       7. The method of  claim 1 , further comprising determining whether the vehicle belongs to the calculated estimation of the attraction domain. 
     
     
       8. The method of  claim 7 , wherein providing the indication for automatic steering comprises indicating automatic mode when the vehicle belongs to the calculated estimation of the attraction domain. 
     
     
       9. The method of  claim 7 , wherein providing the indication for automatic steering comprises indicating manual mode when the vehicle does not belong to the calculated estimation of the attraction domain. 
     
     
       10. The method of  claim 1 , further comprising receiving at least one of the position data associated with the vehicle, orientation data associated with the vehicle, or velocity data associated with the vehicle. 
     
     
       11. The method of  claim 1 , wherein calculating the estimation of the attraction domain and providing the indication for automatic steering are repeated periodically or continually. 
     
     
       12. An apparatus to efficiently position an automatic steering vehicle to move along a predefined path, comprising:
 a processor operable to calculate an estimation of an attraction domain using a current position of the vehicle, a current orientation of the vehicle, and a current steered wheels angle of the vehicle, and further operable to generate a control signal associated with deviation of the vehicle from the predefined path. 
 
     
     
       13. The apparatus of  claim 12 , wherein the estimation of the attraction domain comprises an ellipsoidal estimation of the attraction domain. 
     
     
       14. The apparatus of  claim 12 , wherein the processor is located remote from the vehicle. 
     
     
       15. The apparatus of  claim 12 , wherein the processor is located in the vehicle. 
     
     
       16. The apparatus of  claim 12 , wherein the processor is operable to process navigation data received from a positioning system, the navigation data comprising at least the current position of the vehicle. 
     
     
       17. The apparatus of  claim 16 , wherein the positioning system comprises a satellite positioning system. 
     
     
       18. The apparatus of  claim 16 , wherein the navigation data is processed suitable to calculate the estimation of the attraction domain or to generate the control signal. 
     
     
       19. The apparatus of  claim 12 , comprising a memory storing data representative of the predefined path. 
     
     
       20. The apparatus of  claim 12 , wherein calculation of the estimation of the attraction domain includes using the predefined path. 
     
     
       21. A non-transitory computer-readable storage medium comprising computer executable instructions for providing stability indication of an automatic steered vehicle moving along a target trajectory, the instructions comprising instructions for:
 generating an estimation of an attraction domain; and 
 generating a control signal representative of deviation of a current state of the vehicle from the target trajectory. 
 
     
     
       22. The computer-readable storage medium of  claim 21 , wherein generating the estimation of the attraction domain comprises generating an inner ellipsoidal estimation of the attraction domain. 
     
     
       23. The computer-readable storage medium of  claim 21 , wherein generating the control signal comprises generating the control signal using feedback linearization. 
     
     
       24. The computer-readable storage medium of  claim 21 , the instructions further comprising instructions for:
 generating an indication of stability to automatically steer the vehicle; and 
 automatically steering the vehicle using the control signal. 
 
     
     
       25. The computer-readable storage medium of  claim 21 , wherein generating the estimation of the attraction domain is based on position data associated with the vehicle. 
     
     
       26. The computer-readable storage medium of  claim 21 , wherein generating the estimation of the attraction domain is based on orientation data associated with the vehicle. 
     
     
       27. The computer-readable storage medium of  claim 21 , wherein generating the estimation of the attraction domain is based on a steered wheels angle associated with the vehicle. 
     
     
       28. The computer-readable storage medium of  claim 21 , wherein generating the estimation of the attraction domain is based on the predefined path.